1. Field of the Invention
The present invention relates to mechanical switches and, more particularly, to switches for use in microwave applications.
2. State of the Art
In the field of microwave switching (i.e., wherein microwave signals are selectively switched from a first coaxial conductor to either a second or third coaxial conductor) mechanical switches are well known. In comparison to diode switches, however, mechanical switches are often considered to have inferior reliability with respect to repeatability over a large number of switching cycles (e.g., five million switching cycles).
Further in comparison to diode switches, microwave switches of the mechanical type incorporate moving parts that can wear and degrade performance. Accordingly, there exists a need in the art for a mechanical switch which does not exhibit noticeable performance degradation due to wear of moving parts over a large number of switching cycles (e.g., five million switching cycles).
Problems with conventional mechanical switches include: (1) compromises in performance due to part dimensions and spring properties, (2) high sensitivity in switching performance due to changes in magnetic properties and due to the relative orientation of the magnet and armature, (3) production of impact debris due to the armature striking the solenoid pole faces, (4) changes in effective area of the gap between the armature and core face as the core face is deformed by successive impacts with the armature, (5) the need for an adjustment mechanism to compensate for changes in magnetic properties, (6) wear in bearing areas of a slider mechanism due to torque produced by asymmetric leaf springs, (7) repeatability in jumper positioning in the ON and OFF states, (8) debris caused by repeated striking of the jumpers against mode suppressors which are used to absorb unwanted energy when the jumpers are in the OFF state, (9) breakage of the jumpers due to fatigue from repeated impact with the microwave cavity wall, and (10) less than optimum isolation due to the presence of a wide gap between the jumpers and the microwave cavity wall when the jumpers are in the OFF state. Accordingly, there exists a need in the art for a mechanical switch which overcomes the aforesaid problems.